1. Field of the Invention
The invention relates to a piece of resting furniture such as a bed or chair. Further, the invention also relates to an actuator system applied in the furniture, and moreover the invention relates to a patient lift.
2. The Prior Art
The piece of resting furniture dealt with is of the nature which could be adjusted by means of at least one actuator. In hospital and care beds an upper frame carrying the mattress could be raised and lowered by means of actuators and also the back and leg rest of the support for the mattress could be adjusted by means of actuators. Also, leisure chairs in nursing homes could be adjusted by means of actuators. The types of actuators normally used is linear actuators with a thrust rod, see, e.g., WO 02/29284 A1 Linak A/S. A special linear actuator for beds is a double drive, see, e.g., WO 02/24035 A1 Cimosys A G. An example of a rotary actuators could be found in WO 01/17401 A1 Linak A/S designed especially for beds. For recliners or leisure chairs, linear actuators without a thrust rod, where the application is directly fixed to the spindle nut, are known (see, e.g., WO 96/12123 Koch sold by OKIN Gesellschaft für Antriebstechnik mbH).
In hospitals and nursing homes it is for some types of patients necessary for the nursing staff to know whether the patient is lying in the bed or is about to leave it (called pre-egress) or has left it (called egress). Such beds are among others described in U.S. Pat. No. 4,934,468 Hill Rom Co. Inc, and U.S. Pat. No. 5,276,432 Stryker Corp. In beds furnished with a weighing system for weighing and/or monitoring the weight of the patient, the weighing system could be employed for monitoring of the patient's position in relation to the bed. In such types of beds it is straight forward to incorporate an alarm in case the patient has left the bed. In more sophisticated elaborations it is also possible to detect if the patient is about to leave the bed or to detect the position of the patient in the bed. However, as such bed constructions basically are meant for weighing and/or monitoring weight of the patient, load cells with high resolution and of high quality are used, which also renders such constructions expensive. This means that such beds are only used within hospitals, and even finds restricted use, namely for patients requiring special treatments or special attention.
To improve care of patients on a general level in hospitals and nursing homes and to improve the working conditions for the staff, it would be helpful with a more widespread use of beds with at least an egress function.
Thus, it is an object of the invention to provide an egress function which makes it possible to implement in hospital or care beds on a larger scale.